Some editors and teachers use Track Changes to edit and respond to writing in Word documents. This tool tracks any suggested changes including deletions, comments and insertions, formatting changes, and moved content.

So, the assignment is to read someone else’s article and peer-edit. Responding to the writing of a classmate is far more than merely saying “this is really good”.
The ideas listed here are ways for you to actually assist a classmate with their writing, even if you feel unqualified to do so. (You can also use this guide to assess your own writing!)